Here's my find-and-replace command, copied from some StackOverflow answer at some point in time: https://github.com/tubbo/home/blob/master/bin/repl

It uses Ag to search over each file and Perl to perform the necessary regex. It also creates *.bak backup files in case I replaced something that wasn't supposed to be replaced, but will remove those backup files if I'm in a Git repo (because I basically had to `git clean -f` every time after using this command...so I just wrote it into the command)